Xtremehorticulture

Xtremehorticulture of the Desert

Figs Are “Oasis” Plants

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Q. I have ‘Brown Turkey’ figs that are ten and twelve years old. This year the fruit is large, but as they are lightly purpling up, the skin has wrinkled, and the fruit is very dry within. Some were black, like smut, but mostly dry, and lumpy. A. Check the amount of water your figs are getting. Most figs should be watered twice a week right now. All fruit trees should not be short on water during its production of fruit. We are quickly approaching day/night temperatures (and wind) (mid June) that require watering figs three times a week. The higher temperatures demand more water for production to continue. Just don’t water any fruit trees more often than every other day. Many plant leaves close their stomates (most of the water lost is due to transpiration) during the night. But that is only part of the problem. Plant ET (evapo-transpiration) accounts for evaporation from the soil as well as transpiration mostly from plant leaves. Water management (water lost from its leaves as well as the soil surface) must account for both. This is why covering the soil with mulch of either rock or wood chips is so important. During the heat, covering the soil with two to three inches of mulch can give you at least one extra day of watering each week!             The next irrigation occurs when water from the soil reaches about 50% (half) or leaf scorching and branch/twig death may occur. The water in the soil is like the gas tank of a car, but only let the tank get half empty before filling it again with an irrigation. I haven’t had much luck growing ‘Brown Turkey’ figs. Other figs I have had no problems. Some people can’t grow some plants.             Figs produce two crops of fruit; an early crop (Briba) and a later (Main) crop. Early fig production, in my experience, is less affected by a lack of water than production of a main (later) crop. The early figs (Briba crop) are usually fine with a smaller amount of water. I don’t think it’s diseased.

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Plant Landscapes “Wet”

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Q. We had six 24″ box bay laurel trees and one 24″ olive tree planted in April of 2021, three years ago.  We water once a week for one hour with four, two gallon per hour emitters in the spring. We are not sure if they are doing well and would appreciate your expert advice. A. Thank you for telling me how you are irrigating these trees. If it were me, I would flood the area around the tree, a single time, with water now. Don’t wait. Use a $12 stationary sprinkler at the end of a hose and adjust the watering pattern from six to eight feet. Water this way for one hour. Next, I would increase the four emitters to four gallons per hour rather than two gallons per hour. I would still water for one hour.  As trees get bigger, they need more water. I believe you did not give these trees enough water when they needed an increase in water. A normal response to a lack of water is leaf drop and thinning of the canopy. I doubt it is a disease problem. I would first guess it’s not getting enough water as temperatures increase. This is normally taken care of by increasing the number of times you water per week. In your case, I think the two gph emitters did not release enough water. Replacing the emitters is sometimes a better solution than increasing the water output for ALL the plants. This way your watering time does not change. Some people plant these trees in dry soil. Make sure they are planted “wet”. Watering now with a stationary sprinkler wet all of the roots immediately. Make sure those 4 gallons per hour emitters are from six to twelve inches from the trunk of the trees. All of the soil should be wet between irrigations. These are not desert trees (xeric) but both are water loving mesic trees. Just for your information the olive tree will grow about 30 feet tall if left alone (they should be planted no closer than 20 feet apart). Olive trees can handle the heat. The bay laurel will grow about 20 feet to 25 feet tall but struggle with extreme heat. Both are considered “mesic” in their water use.

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My Myers Lemon Tree Just Crashed

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Q. One of our mature Meyer lemons just crashed. I think we are giving it enough water. Were watering it once a week. I fertilized it and applied Kerex iron. A. It is the end of May. Make sure it is not water problem. Right now, we should be applying water to it (at least half of the spread of its canopy and to a depth of 18 to 24 inches) twice a week starting about 2 to 3 weeks ago for most soils and fruit trees in the Las Vegas area. That is the first thing to take care of before we start correcting other problems. It is mesic in its water use, not a desert tree. During spring is a dangerous time to fiddle with the amount of water. If you skimp on water while the fruit is getting larger, then it may make fruit smaller because you were not applying enough water. Enough water MUST be available to the fruit as they enlarge if you want the fruit larger.  Never daily. That’s a no-no. If water is applied too often then diseases are a problem. The first thing to do is make sure there is enough water present for fruit formation, but not watering daily so that diseases develop. Right now for most soils we should be watering twice a week in Las Vegas and using a thick surface mulch.             Next are the nutrients. For the fruit and trees to be healthy and to produce healthy fruit, all nutrients should be present. That’s the purpose of wood chips plus fertilizer. They rot or decompose when water is present. That’s why we fertilize fruit trees at least once or twice a year with the macro nutrients nitrogen, phosphorus, and potassium (NPK). Iron applications are different. Iron is a MICRO nutrient and not available in many of our desert soils because of the soil pH. Iron is needed in much smaller amounts, but it is still very important. In fact, it is essential (along with manganese and zinc). All three are affected a lot by a soil’s alkalinity or acidity (pH). All three of these micro nutrients are affected by (in our soil especially iron) their availability in a high pH desert soil. Any yellowing of leaves can be any of these three nutrients! But iron is MOST LIKELY in our desert soil. Many of our iron fertilizers (any of the older iron types) ONLY works if the pH (alkalinity) of our soil is measured at 6.8 or lower. EDDHA chelated iron was made so that it works at any soil alkalinity (any pH)! Any type of iron, including EDDHA, must be applied to our soil only from February through about May. The closer to February, the better. Let’s clear up the water and mulch problems first. After that is done, we can talk about other tree issues that might pop up. Water is the biggest problem (not enough or watered too often) your tree is facing!

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Bird Scaring Devices for Fruit Trees

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Q. Can you recommend something that can be used to discourage birds from eating my figs and peaches? A. Peaches are a lot easier than figs. Figs must be picked when they are ripe. Peaches will ripen off the tree. As soon as you see bird pecks on firm peaches, harvest them. Don’t wait for them to get soft. The birds know when they are ripe enough to eat. A few days on the shelf at room temperature and they will be ripe enough to eat. If you are not sure whether to harvest the peaches or not, look at their “background color” or when they turn from green to either yellow or red with yellow, depending on the variety. If you are still not sure, mark your calendar. Do this in combination with bird pecks. If they are ready to harvest in early June, mark your calendar and start checking them in late April for bird pecks. Start harvesting them the day you see bird pecks. Or harvest them when they turn color; when they are “firm” and no longer “hard”. At that stage, they are tree ripe! A couple of days out of the sun and at room temperature and they will be ready to eat. Peaches that ripen during hot weather are ready to harvest over a period of about two weeks and earlier peaches (April and May) are closer to three weeks. Harvest the ones that are ready first and then wait a few days and harvest more. Peaches will ripen first where they get the most heat. That means the south and west sides and top (in full sun) are first, then the more interior ones (where its shady and cooler) are ready in a few more days. Figs are only harvested when they are tree ripened. That’s the difference between climacteric fruit (peaches, apricots, and others) and non-climacteric fruit (figs, grapes, cherries). The best thing I can tell you is to harvest the non-climacteric fruit early in the morning, as early as possible. Unless you want to spend lots of extra time and extra money. Harvesting figs are tough because they are non-climacteric. Peaches are easier if you harvest them a bit early, like I explained, and let them ripen off the tree. Sometimes “dumb” or inexperienced birds peck and ruin the hard, green fruit but that is rare. We have had no luck with hanging tinsel, CDs, owls, etc. When the birds got used to them, they always had a field day with the fruit. Most of the odd ball things that scared birds, and hung in those trees within about two weeks of harvest, were effective. Longer than about two weeks and the birds started to get used to any scaring devices and devastated the fruit. The University orchard in North Las Vegas was close to an RC runway and park. We used to joke about getting someone to “buzz” the University orchard, but we never did that. Might be a good excuse to buy an RC plane!

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Root Depth of Newly Planted Trees

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Q. I know you water a boxed tree to 24” deep but do you water a new tree to 24” deep even if is a sapling in a 15-gallon pot? A. What we have done with newly planted fruit trees (planted among established fruit trees) is move drip emitters closer to the trunk during the first year of establishment. These newly planted trees are irrigated 18 to 24 inches deep during this time, but the emitters are spaced on top of the rootball, close to the trunk. By fall, newly planted trees will become “established” and acclimated.  The right number of drip emitters can be added for future growth at that time. The newly planted trees will become established when temperatures cool off by the fall months (usually by the end of September or early October). Planting during the spring months (late January through March) gives these plants time to get established by fall. Spring or early summer planted plants will usually get established by the following fall. Fall planting of trees and shrubs have a cool fall and the following spring to get established. Planting during the early summer months (April and May) will work but does not give them as many months to get established. Once plants get established (provided the planting hole was dug wide enough) during the fall months the water can be applied normally, with the other plants.

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Eliminating Ants

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Q. What is the best way to get ants out of my potted plants outside? A. The best chemical control method I have seen is a bait product made for several kinds of ants and manufactured by Amdro. I am sure other companies that make similar products are just as good. Ants take this bait back to the nest where it is fed to the queen as well as other ants. Control of ants is within 24 hours if done right. The usual reasons for failure are because the bait was not placed near the nest or because it became wet. If you use it, find the nest or opening to the ground. Place it near the nest in the ground. This product must be used dry so use it in containers when it is cool and after an irrigation. Read the directions for this bait and follow them precisely.

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Using Fire to Control Roots

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Q. We are planting a 30-gallon apricot tree. The hole is large and deep, but the bottom has lots of thin roots from nearby trees. I took out most of the bigger ones. Can I torch these small ones? A. Roots no longer attached to the “mother” plant can be “torched”. Using fire to kill roots only kills the roots a few inches from the fire. Killing roots is due to the heat produced by the fire. During the summer, clear plastic can be used to kill roots during the day. All roots and diseases are killed at 180F in 30 minutes and allowed to “solarize”. That’s the temperature and length of time needed to sterilize dry soil 6 to 12 inches deep. If you are still not sure, then sever the roots from the tree with a sharp shovel.             By the way, it is less of a problem if the planting hole is dug wider but not deeper. When digging a planting hole, it is recommended to dig the hole three times the width of the roots, but not any deeper than the roots or container unless, of course, there is a drainage problem. Water added to the dug hole should drain overnight.

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Compost for Planting

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Q. I bought straight compost. I told them I was going to use the compost for trees and shrubs planted outside. I hope this is the right product I need. I may be looking at other vines soon to cover some other cinder block wall areas. In this case I am thinking about vines that do not require a trellis. I looked at cat claws and read some reviews about how aggressive it can grow and how tough it is to control it in places like the southeast. What do you think about it for wall covers with no trellises in Las Vegas? A. Make sure whatever compost you use is mixed with sand at about one shovel full of compost to three shovels full of sand (25 to 30%). The planting mixture should still be dark, about the same color as straight compost. Straight compost may be too “hot” for plants that grow in soil and may injure them. The only thing municipal compost is in short supply is potassium, a macronutrient but high in nitrogen, phosphorus and lots of minor elements. Use Straight Compost as a Fertilizer You can also use straight compost as a fertilizer but be careful with it. Municipal compost can be “hot” (high in salts) so don’t put municipal compost closer than about 18 inches from the plants trunk or central growing point and then water it in. Soak the fertilized area with lots of water! Apply straight compost lightly. If you are not sure, then ask how to apply it when using it as a fertilizer. The soil should be close to the same texture as the surrounding soil but be darker and hold water better. You never want to use compost, straight, in a planting hole because it contains a higher level of different types of salt and is very different in its texture (water holding capacity, WHC). Cat Claw Vine A good choice is the cats claw vine for climbing on hot (south or west facing) walls. It is watered as a “mesic” vine or shrub. Cat claw vine is not a desert plant, but it does handle desert dry heat. It will not grab onto walls if the wall gets hot, above 145F. Those temperature and higher will be on hot-facing walls in full sun during the early and mid-summer months. During cool weather it will self-climb, but not on a hot wall. When the wall gets too hot, the new tendrils “burn” and the vine will stop climbing until cooler weather. The vine will reclimb again when temperature of the wall cools off in the fall. If you don’t over water it, it wont be a problem. It will easily cover the wall of a two story home if watered abundantly. Check with a local nursery for available choices of other desert vines. Have you tried using either paint or a texture (like cut reeds or cut bamboo) to cover the wall instead of vines? These additions to your landscape don’t use any water. Water use is important in the desert. Cut bamboo and reeds will need maintenance or replacement every few years.

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Vines for Desert Landscapes?

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Q. I recently planted two vines in my backyard; a Bank’s rose and a tangerine crossvine. I got the amended soil at Viragrow and the wood chip mulch at the demonstration orchard as you suggested. Shall I use wood chips mulch for both vines or not? How often shall I add the amended soil or fertilizer to the vines after having planted them? A. When in doubt, use wood chips as a surface mulch. Mulch of all types (including rock mulch) saves water and reduces weeding. Wood chip mulch, unlike rock mulch, “rots” into the soil and increases the organics of desert soil. Rock mulch doesn’t. After planting, apply this mulch in a circle six feet wide from the trunk and 3 inches deep. When the wood chips get sparse, freshen this layer with new wood chips. Keep them away from the trunk until the plant gets woody (five or six years after planting). The idea is to have the wood chips decompose or rot during the first few months and add “organics” to the soil. The wood chips will decompose in less than six months during warm and hot weather. When using a fertilizer, the type is not important but getting the nutrients it needs when its young, and applied to the right places, is important. After the hole is dug, apply a fertilizer high in phosphorus (something like a 16-20-0) at the bottom of the planting hole (a handful of fertilizer added to the soil at first when backfilling). A single application of fertilizer once a year in early spring is all the plant needs. After planting, use a landscape fertilizer no more than once when you see new growth. Neither vines are truly “desert” in origin. ‘Tangerine Beauty’ Crossvine The ‘Tangerine Beauty’ crossvine (Bignonia capreolata ‘Tangerine Beauty’) is a native, naturally climbing vine, found in the southeastern United States. It is found from Florida to Maryland and west to Texas. It is a vigorous vine with evergreen leaves and two-inch reddish, trumpet-shaped flowers. It can cling to structures like trellises, fences, arbors, and brick or rock walls. It blooms in the spring with repeat blooms throughout the growing season. It’s an early nectar source for butterflies and hummingbirds, and the flowers attract hummingbirds. Lady Banks Rose Unlike the crossvine, the lady banks rose flowers (yellow or white) only once in the late spring and is not a natural climber. Strong support must be provided. It grows to about 25 feet and is evergreen only in warm climates.

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